The International Atomic Energy Agency will receive an official letter about the agreement "within a week," Mehmanparast said.

The exchange will occur about a month after Iran received official approval from the Vienna Group, made up of representatives from Iran, France, Russia, the United States and the IAEA, Press TV said.

Diplomats said the agreement -- the result of trilateral talks among Iran, Turkey and Brazil -- could revive an earlier U.N.-backed proposal for Iran to exchange fuel outside its borders, The New York Times reported.

Word of the agreement began filtering out Sunday after talks in Tehran involving Brazil's president, Luiz Ignacio Lula da Silva, Turkish Prime Minister Recep Tayyip Erdogan and Iranian President Mahmoud Ahmadinejad. A Turkish Foreign Ministry spokesman said Iran and Turkey reached agreement on the "principles" to revive the stalled nuclear fuel-swap deal backed by the United Nations.

Unclear was whether U.S. President Barack Obama's administration, which has insisted on a new round of sanctions over Iran's nuclear program, would accept a new version of the original United Nations-based deal for a fuel exchange. The original terms were thought to be desirable to the United States and Western allies because Iran would have temporarily relinquished most of its uranium.

Mehmanparast said Turkey, which doesn't enrich uranium, agreed to serve as the venue for the fuel exchange, the Los Angeles Times reported. It wasn't clear whether Turkey would be a guarantor for the low-enriched uranium or if the material would be shipped to a nation with refinement capacity.

Iranian President Mahmoud Ahmadinejad turns a camera on photographers after Iran, Turkey and Brazil signed an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Brazilian Foreign Minister Celso Amorim, Brazilian President Luis Inacio Lula da Silva, Iranian Foreign Minister Manouchehr Mottaki, Iranian President Mahmoud Ahmadinejad and Turkish Prime Minister Recep Tayyip Erdogan join hands after the three countries signed an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Iranian President Mahmoud Ahmadinejad (C) shows a victory sign to reporters after Iran, Turkey and Brazil sigend an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Brazilian Foreign Minister Celso Amorim, Iranian Foreign Minister Manouchehr Mottaki, and Turkish Foreign Minister Ahmet Davutoglu (L to R) shake hands after signing an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Brazilian Foreign Minister Celso Amorim, Iranian Foreign Minister Manouchehr Mottaki, and Turkish Foreign Minister Ahmet Davutoglu (L to R) sign an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Turkish Prime Minister Recep Tayyip Erdogan is seen as Iran, Turkey and Brazil sign an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo

Brazilian Foreign Minister Celso Amorim, Iranian Foreign Minister Manouchehr Mottaki, and Turkish Foreign Minister Ahmet Davutoglu (L to R) sign an agreement to ship Iran's low-enriched uranium to Turkey in exchange for fuel for a nuclear reactor in Tehran, Iran, on May 17, 2010. Iran signed an agreement to swap its uranium in Turkey for enrichment, hoping to avert new international sanctions. Brazil helped broker the deal. UPI/Maryam Rahmanian | License Photo